The present invention relates to in-vessel composting. More particularly, the invention relates to a new and improved method and apparatus for in-vessel composting for improved fluid use efficiency and pollution control.
It has long been recognized that vast quantities of organic waste materials are being produced annually. As the world's population increases so does its capacity to produce waste materials. The disposal of these waste materials represent difficult disposal problems. Their disposal takes up valuable land, and monopolizes large amounts of time, energy, effort and capital to overcome the burden of the ever increasing quantities of organic waste material.
Composting provides an important part of the solution to reduce the problems associated with organic waste material disposal. Further, composting can provide materials that serve as important basic building block materials for such industries as the construction industry and the agriculture industry.
Composting for the most part is a time consuming, energy intensive, non-uniform process. Various composting apparatus and methods are shown in U.S. Pat. Nos. 3,114,622; 3,357,812; and 4,203,755.
U.S. Pat. No. 3,114,622, issued Dec. 17, 1963 to W. Hardy, discloses an apparatus utilized as a waste material converter. The converter includes a plurality of screw augers having holes therein for the introduction of air into the waste pile. U.S. Pat. No. 3,357,812, issued Dec. 12, 1967 to J.R. Snell, discloses an apparatus for composting organic waste material utilizing a fixed pipe system located beneath the composting pile for accomplishing reversible air flow. U.S. Pat. No. 4,203,755, issued May 20, 1980 to K. Ruckstuhl, discloses an apparatus for treating waste material wherein a plurality of pipes are disposed within the composting mass for the discharge of gaseous products of decomposition.
One of Applicant's previous inventions provides a device that equalizes air distribution throughout the compost pile as set forth in U.S. Pat. No. 4,410,349, issued Jul. 8, 1983 to Applicant. This equalization reduces air pressure thereby reducing horsepower, and the associated energy needed to generate the required air distribution. The air distribution equalization enhances process controls and removes or inserts moisture in the system, as desired to improve composting efficiency. Further, the device reduces the overall length of the process air path to prevent compost pile hot spots and dead spots to provide a more uniform composting process. That invention provides improved fluid flow control for the air distribution lances utilized in compost piles.
Another of Applicant's previous inventions, as set forth in grand parent U.S. application Ser. No. 643,080, incorporated herein by reference, filed Aug. 22, 1984, now U.S. Pat. No. 4,837,153, provides an improved fluid flow control method for composting organic waste material. The improved fluid flow control is provided by a lance having at least two separate fluid flow zones to provide a fluid flow profile in the compost. The flow zones are provided by an outer porous wall tube with a control insert tube therein, having a plurality of openings along the length thereof and spaced from the wall by gaskets to form the separate flow zones. The control insert tube can also include an internal tube valve therein, which allows for adjustment of the fluid flow through the insert openings.
A plurality of the lances disclosed in U.S. Pat. No. 4,837,153 are preferably used in the composting system. The lances are coupled to a manifold system for the injection and evacuation of fluid or air flow in distinct substantially uniform injection and evacuation patterns substantially equally spaced from one another. The manifold defines the injection and evacuation patterns in a substantially vertical plane, while the lances define the patterns in a horizontal plane.
In yet another of Applicant's inventions, described in copending application Ser. No. 190,340, filed May 5, 1988, there is provided a new and improved biofiltration air control distribution method and system for use in earth filters or biotowers. The biofiltration apparatus described in that application uses the lances described in U.S. Pat. No. 4,837,153, the disclosure of which is incorporated herein by reference, preferably coupled to a manifold system for the injection and evacuation of fluid or air flow in the biofiltration apparatus.
While the improved fluid flow control methods and apparatus disclosed in Applicant's prior applications and patents have provided marked improvements to in-vessel composting systems, in recent times of stricter environmental regulations it has become even more desirable to minimize stack discharges and emissions during the operation of a compost facility. This is especially true in urban areas where any discharge of malodorous compounds is unacceptable. The new in-vessel composting system described and claimed herein not only reduces the quantity of fluid discharged into the atmosphere from the composting process, but also removes particulates and noxious and odorous gases from the exhaust fluid before it is discharged.